Transport device, more especially for screen printing machines

ABSTRACT

A transport device, more espeically for screen printing machines, with conveying chains which run parallel and spaced apart and hold the workpieces to be moved in receptacles, wherein each receptacle which carries one end region of a body, is formed from two catches which are provided on two adjacently running conveying chains which face each other, and have lugs which engage the receptacle, which is open upwards, the said lugs having faces which are vertical or inclined with respect to the longitudinal direction of the chains, and in which two chains are movable with respect to one another in the longitudinal direction of the chains to form differently shaped or dimensioned receptacles.

[ 1 Dec. 18, 1973 llnited States Patent [1 1 Kamrnann TRANSPORT DEVICE, MORE ESPECIALLY FQREIGN PATENTS OR APPUCATIONS FOR SCREEN PRINTING MACHINES [75] Inventor: Wilfried Kammann,Suedlengern,

Germany Primary ExaminerEdward A. Sroka A!t0rneyAmster & Rothstein [73] Assignee: Werner Kammann,

Buende-Westphalia, Germany June 3, 1971 [5 7] ABSTRACT A transport device, more espeically for screen printing machines, with conveying chains which run parallel [22] Filed:

[21] Appl. No.: 143,635

and spaced apart and hold the workpieces to be moved in receptacles, wherein each receptacle which carries one end region of a body, is formed from two catches. which are provided on two adjacently running conveying c [30] Foreign Application Priority Data June 19, I970 Germany.................., P 70 23 045.4

198/131, 198/189 hains which face each other, and have lugs 3 15/10, 365g 17/42 which engage the receptacle, which is open upwards, Fleld of zg/ l fl the said lugs having faces which are vertical or in- {521 US. [51] Int. [58] 198/173,

clined with respect to the longitudinal direction of the chains, and in which two chains are movable with re- [5 6] References Cited UNITED STATES PATENTS 198/179 X 198 189 X i |/98/|79 11 Claims, 7 Drawing Figures PMENIEUBEP. I 8 I973 3; SHEET 2 n; s

III! n 40 39 mm 2.

PAIENIEDnEr, 1 8 I975 SHEET 30F 3 TRANSPORT DEVICE, MORE ESPECIALLY FOR SCREEN PRINTING MACHINES PRIOR APPLICATION In Federal Republic of Germany on 19th June 1970 and numbered G 70 23 045.4.

One object of the invention is the production of a transport device, more especially for screen printing machines, with which workpieces having different cross-sections and different sizes of cross-section can be securely moved and positioned.

Another object of the invention consists of equipping the transport device with receptacles which hold the workpieces while being transported, and which enable their surfaces to be printed right up to the two end regions.

Furthermore, workpieces printed on both sides in this transport device are moved securely without damage from pressure.

Another object of the invention is the production of a transport device which can deliver the workpieces in a simple, regular and secure manner, according to position, from one transport device to a further transport device; the workpieces must be held securely in position, and free of damage during delivery from one transport device to another.

In a preferred embodiment a transport device for screen printing machines, is equipped with four conveying chains having receptacles for the two end regions of the workpieces such as bottles, to be transported arranged on them. The conveying chains are arranged in pairs close together near the ends of the workpieces, and each receptacle, which in each case carries the end region of a workpiece, is formed from two catches which are provided on two respective adjacently running conveying chains. The catches point towards each other, and their surfaces form a receptacle, which is open upwards. The said surfaces are vertical or inclined with respect to the longitudinal direction of the chains.

The adjacent conveying chains of a pair, which carry one end region of a workpiece, are shiftable towards one another in the longitudinal direction of the chains, so as to form receptacles of different dimensions, and the co-operating conveying chains move continually around chain wheels. The two chain wheels of each pair of chains are mutually rotatable for the purpose of shifting the chains, and all chains are adjustable towards one another in a direction normal to their length.

A delivery arrangement is provided in a guided region of the conveying chains, which takes the workpieces from the conveying chains, turns the workpieces and then delivers them to a further transport arrangement which is provided with holding plates having slidable abutment surfaces. The plates are movable axially towards one another, and clamp the workpieces on oppositely situated front sides; the plates are arranged in bearing discs of the guide shaft in a turning region at spacings'which correspond to the spacing of the conveying chain receptacles, and are held in position'for receiving and delivering the workpieces. Axial plate movement is effected by an index plate with control surfaces. (running surfaces), and such plate is axially twistable by a disc cam over a lever mechanism.- The running surfaces of the index plate co-operate resilof catches, which are angled towards one another, and

which therefore have their workpiece receiving surfaces substantially in one plate, permit printing of the workpieces lying in the direction of transport substantially to their end' regions.

An embodiment of the invention is shown in the accompanying drawings, in which:

FIG. 1 shows a side view of a transport device for a screen printing machine with catches provided on parallel-running chains;

FIG. 2 shows a vertical section through the same transport device with four chains having catches, arranged beside one another, the catches of two chains forming a receptacle for the workpieces to be conveyed;

FIG. 3 shows a top plan view of two chains of the transport arrangement, with two catches having the workpiece contacting parts in line, in the transport direction;

FIG. 4 shows a chain link with a support bar for the body to be imprinted, partially in section;

FIG. 5 shows a side view of a part of the transport device, with a delivery position in a guided region, and a further transport arrangement acting in conjunction with this delivery portion along the section line II in FIG. 7;

FIG. 6 shows a plan view of one part of the delivery arrangement with a bearing disc having plates which hold the workpieces to be transported, and an index plate which controls the plates in an axial shifting movement;

FIG. 7 shows an end view of the transport device with a delivery arrangement in a delivery position, partially in section.

A transport device for a screen printing machine, has four chains 10 13 which run parallel in the transport direction, of which chains 10 and 11, and 12 and 13 are combined into pairs. Each pair of chains 10 and 11, and 12 and 13 possesses receptacles 14 to hold the ends of workpieces 15, such as bottles, to be moved and printed, (FIGS. 1 3).

Each receptacle 14, which carries an end region of a workpiece, is formed from two catches l7 and 18, and 19 and 20, these being located on two adjacently running chains 10 and 1 1 and 12 and 13 and point towards each other. Their surfaces 16 are arranged either vertically or inclined with respect to the direction of movement of the chains.

The catches 17 to 20 which are fastened to the chains wand 11, and Hand 13, are designed so that they are angled towards each'other. Each catch 17 to 20 possesses a'foot 21 which is fastened to the outside of the chains, and which is pointed towards the adjacent chain 10 to 13, and a lug 22, which may be vertical and defines the surface 16 of the-receptacles. These lugs 22 may also be tilted, so that they are inclined towards the chain to 13. The catches l7 and 18, and 19 and 20 may also be pointed or curved towards one another.

These lugs 22 of the catches 17 to 20 of each receptacle 14 preferably extend in a common plane, and each receptacle 14 is formed from two catches 17 and 18, and 19 and 20, which are arranged behind one another in the direction of movement of the chains (FIG. 3).

The lugs 22 of the catches 17 and 18, and 19 and 20 may alternatively be located beside each other at a small space apart, (FIG. 2).

Each catch 17 to 20 has a limitation surface 16 which runs at a sharp angle, and a limitation surface 16 which runs at a right angle to the chain 10 to 13, so that differently shaped receptacles 14 may be formed.

The limitation surfaces 16 which are provided on opposite sides of the lugs 22 in the direction of movement of the chains, together with identical limitation surfaces 16 of catches 17 to 20 located in front or behind, enable prismatic, square, or rectangular receptacles 14 to be formed so that with this transport device, workpieces having a circular, oval or angular crosssection can be transported.

The catch 17 or 19 of a chain 10 or 12 forms with the catch 18 0t 20 of the adjacent chain 11 or 13, a receptacle 14, in which one end region of the workpiece 15 is mounted. As the lugs 22 which form the receptacle 14, i.e. the lugs of catches l7 and 18 and 19 and 20 are angled in pairs towards each other and are substantially in line, receptacles 14 can be formed which accept quite small parts of workpieces 15.

In order to be able to form differently shaped and di mensioned receptacles 14, the two chains 10 and 11, and 12 and 13, are adjustable with respect to one another in the longitudinal direction of the chains; it is preferable to design all the chains 10 to 13 so that they are shiftable in the longitudinal direction so that the receptacles 14 facing one another are of variable size and/or of a different shape, which enables workpieces 15, such as conical bodies, having a different crosssection over their length, to be transported.

The two chains 10 and 11, and 12 and 13 which respectively support one end region of the workpiece to be printed, pass around chain wheels 23 and 24 which can be relatively rotated and fixed than fixed so that by axial rotation of the chain wheels, variation of the relative positions of the chains 10 and 11 or 11 and 12 takes place.

The two associated chain wheels 23 and 24 are arranged on a boss 26 which is fixed to a shaft 25, and there are screws 28 which pass through elongated holes 27 in the chain wheels and engage in the boss 26. The chain wheels are thus relatively adjustable over a required range which may be 180.

Upon rotating a chain wheel 23 or 24 through its turning range, the associated chain moves axially; if both adjacent chain wheels 23 and 24 are rotated both the chains 10 and 11, and 12 and 13 move axially, and a total relative movement corresponding to a wheel displacement of 360 is possible.

The boss 26 possesses a lug 26a, which holds the two chain wheels 24 spaced apart. This spacing is such that the catches l7 and 18 and 19 and 20 run in with their limitation surfaces 16 or the lugs 22 in line.

A distance piece 29 which is placed on the boss 26, and lies between the lugs 26a and a chain wheel 23 and 24, holds the adjacent catches l7 and 18, or l9 and 20 with their lugs 22 at a certain spacing from each other, but lying in line.

This transport device is particularly suitable for a screen print machine; the device runs below a printing attachment (holder 30, printing template 31 and doctor blade 31a and delivers the workpieces 15 directly to the holding arrangement 30, which feeds the respective workpiece 15 to the printing template, or holds them during printing in the receptacles 14.

The bosses 26 which carry the chain wheels 23 and 24 are located at an axial spacing from each other and are adjustable on the shaft 25, so that the receptacles 14 can be made to suit various lengths of workpiece.

The movement of the chains l0, 11, 12 and 13 towards each other may be effected by a different form of mounting of the chain wheels 23 and 24 and a different fixation of these wheels 23 and 24 with respect to each other.

As FIG. 4 of the drawings shows, chain links 32 are provided, which form angular receptacles 14 between catches l7 and 18; 19 and 20, these being arranged one behind another in the direction of movement of the transport chains. Each catch is equipped on the inside or outside with a lug 33 which projects upwards, on which is supported an angular or oval workpiece to be printed on both sides. The workpiece rests only on the comparatively small and narrow lugs 33 so that the already printed surface is not interfered with.

The lug 33 of a chain link 32 is provided as part of a lateral flap 32a, and projects slightly upward over the top of the chain link.

The conveying chains 10 to 13 of the transport device which pass over the chain wheels 23 and 24, and are carried by a guide shaft 25, move the workpieces 15 to the printing arrangement 31 in which they are printed, and then accept them again or take them further, in order to feed them to a further transport arrangement 34.

In order to guarantee correct transportation of the workpiece 15 through the subsequent transport mechanism 34, a delivery arrangement 35 is provided near one (guide) region of the conveying chains 10 to 13 about their guide shaft, the delivery arrangement being rotatably arranged, and automatically takes over the workpieces from the conveying chains 10 to 13, rotates them, and afterwards delivers them to the transport arrangement 34 (FIGS. 5 7). This delivery arrangement 35 has plates 36, which are movable axially towards one another, and hold the workpieces l5 clamped between opposed sides. There are abutment surfaces 37 for the workpieces which are slidable.

It is preferable to equip all plates 36 with an abutment surface 37 which holds the workpieces, the surface being made of a layer of plastics material such as polytetrafluorethylene, or sintered metal such as bronze, saturated with a lubricant or the parts may be made of a modular graphite cast iron. These slidable abutment surfaces 37 seize the workpieces which may not be accurately held by the plates 36, and automatically centre them into the trough-shaped acceptance space of the plate 36, and then securely hold them during movement on the part circular track from the transport device 10 to 13, to the transport arrangement 34.

About the guide roller 25 there are two bearing plates 38 outside the conveying chains 10 to 13 which are arranged at an axial spacing to one another and are fastened to the shaft 25, each bearing plate having several adjustable plates 36 which face one another.

To accept a workpiece, facing plates 36 are moved towards each other, and thereby hold the workpiece firmly clamped along the entire transport route, and release it again by axial movement in opposite directions after the termination of the transport route.

The relative angular spacing of the individual plates 36 inside a bearing plate 38 corresponds to the spacing of the receptacles 14 of the conveying chains to 13 which hold the workpieces so that these are fed uniformly to the plates 36 which run synchronously with the conveying chains 10 to 13. If two facing plates 36 stand in a take-over position, there is also a receptacle 14 with a workpiece 15 in a corresponding position.

The plates 36 hold in the workpiece under compression derived from a spring connected to an index plate 39 which is associated with each bearing plate 38. Each index plate 39 possesses, at least on the revolving edge of its plane running at right angles to the guide shaft 25, two running surfaces 40 and 41 which are located at an axial spacing to one another; each receives half the circumference of a disc on which each plate 36 rests by means of a roller or pin. The two running surfaces 40 and 41 of each index plate 39 accept half a basic shape of the plate 39, and the running surface 40 extends over the entire thickness of the plate, whilst the running surface 41 lies on a part only of the plate thickness; the running surface 41 is on a thinned-down part of the plate 39, so that both surfaces 40 and 41 run at different spacings from the plate surface which is adjacent to the conveying chains 10 to 13.

The two running surfaces 40 and 41 consequently lie on that side of each index plate 39 which is turned away from the conveying chains 10 to 13; the outer running surface 40 determines the release position, and the inner running surface 41 produces the tension position of the delivery arrangement 35.

Each plate 36 is movably mounted on the bearing plate 38 with a guide part 43, and is moved into a tensioned position by a compression spring; this spring continually endeavours to bring the plate 36 into the tension position. The roller 42 is arranged inside of the guide part 43, and by its position on the two surfaces 40 and 41, determines the axial stroke movement of the plate 36. Each index plate 39 is mounted so as to be freely running on the guide shaft 25 and is connected via a link 44 to a disc cam 45 which produces a pivotal movement of the index plate 39 about the guide shaft 35 dependent upon the movement of the conveying chains.

The index plate 39 is pivoted by the disc cam 45 only to move the roller 42, which holds the plate 36 in the waiting position and is supported on the running sur face 40, onto the other running surface 41 so that the roller 42 moves to the inner running surface 41 from the outer running surface 40; the spring can now move the plate 36 axially into the tension position.

The pivotal region of the index plate 39 extends over a predetermined angle and this pivoting produces at one point of the index plate 39 a movement of a roller 42 from the running surface 40 onto the running surface 41, and consequently'seizes the workpieces 15; at one oppositely situated point (point situated opposite at 180) the roller 42 moves from the running surface 41 to the running surface 40, and consequently produces an outward movement of the plates 36 to release the object 15.

The take-over region of the plates 36 is indicated in FIG. 5 of the drawing by A; at this pint A a workpiece 15 is seized by the plates 36 and held up to the point 8; at point B release thereof takes place by axial shifting of the plates 36 the workpiece then being taken over by the transport mechanism 34. If the workpiece is seized at A," the release takes place at B by a pivoting of the index plate 39 in the direction C. The lower-lying surface 41 reaches the region of the upper roller 42, and the higher-lying surface 40 reaches the region of the lower roller 42. The rollers 42 are held in a tension or waiting position between the two points A and B, as they roll off on the surfaces 40 and 41.

The link 44 joins a cranked lever 47 a and 4712 which is pivotable about a fixed point 46, the lever has its arm 47a guided by a curved track 48. The other arm 47b is connected to a push lever 49 which acts upon the index plate 39.

The cranked lever 47a and 47b is pivoted at point 46 and a further lever 47b is also pivoted at point 46, for the other index plate 39, the lever being connected to a second push lever 49, which acts upon the second index plate 39. The pivotal movement of the lever 47a and b, which is produced by the disc cam 45, is consequently transferred to the other index plate 39.

The disc cam 45 and the guide wheels 23 and 24 of the conveying chains 10 to 13 are synchronized, and are propelled together by a driving shaft 50; this driving shaft 50 rotates the disc cam 45, and transfers its rotary movement through an intermediately connected gear mechanism 51 on the guide shaft 14 for moving the chains.

In the case of a further embodiment (not shown) a disc cam with curved tracks is associated with each bearing plate 38 for the axial movement control of the plates 36, which disc cam is mounted on the guide shaft 25, and on which the motion elements 42 for the movement of the plates roll.

Here, the disc cam is provided with curved tracks in such a way that the plates 36 are moved axially towards one another in the tension region, hold the object received, and after termination of the transport movement, are again pushed apart axially.

There also exists the possibility of equipping the delivery arrangement 35 with a bearing disc 38 which has fixed abutment surfaces 37 of a self-lubricating material, and to provide the oppositely situated bearing plate 38 having plates 36 which hold and release the workpieces, with slidable abutment surfaces 37 or with centering points.

As different spacings can occur between the plates 36 and the chain receptacles 14, the workpieces 15 are partially accepted by the plates 35 ie each workpiece is only partially seized by the plates 36. The workpieces are moved by the catches 17, 18 and 19 and 20 to the centre of the plates, by the slidable abutment surfaces 37 and are consequently held throughout with their entire cross-section by the plates 36. Because of the slidable abutment surfaces 37 a satisfactory hold of the workpieces by the plates 36, for further transporting, is secured.

We claim:

1. A transport device, more especially for screen process machines, said device comprising parallel paired conveying chains, receptacles on said chains for the two end regions of workpieces to be transported, each said receptacle comprising two catches located on respective chains of each pair of conveying chains, each said pair of catches which form a receptacle being angled towards each other, a foot on each catch fastening it to one side of a respective chain, a lug on each catch pointed upwards and defining surfaces forming said receptacle, one of said surfaces on said catch forming an acute angle with said chains and the other one of said surfaces on said catch forming a right angle with said chains, whereby the surfaces of adjacent catches which stand at an acute angle to said chains form an angled receptacle and the surfaces of adjacent catches which stand at a right angle to said chains form a rectangular receptacle.

2. A transport device as recited in claim 1 including means for relatively moving the chains which carry one end region of a workpiece to form differently dimensioned receptacles and chain wheels carrying said chains.

3. A transport device as recited in claim 2, comprising a shaft, a boss on said shaft for a chain wheel, and means for effecting relative rotation between said boss and said wheel, and for then fastening said boss and wheel together.

4. A transport device as recited in claim 3, comprising an adjustable distance piece between adjacent chain wheels.

5. A transport device as recited in claim 1, wherein each link of said conveying chains is equipped in the region of their angular receptacles with an upward pointed lug as a support for a workpiece to be printed on two sides.

6. A transport device, as recited in claim 1, comprising a delivery arrangement which is rotatable about a guide shaft to take over said workpieces from said conveying chains, rotate said workpieces through a certain turning range, and thereafter deliver them to a further transport arrangement provided with plates which are axially movable towards one another, to hold said workpieces clamped on oppositely situated sides, said plate having slidable abutment surfaces consisting of self-lubricating material.

7. A transport device as recited in claim 6, wherein said delivery arrangement contains two oppositely situated bearing plates fastened to the said guide shaft plates, several axially movable plates spaced around said shaft at points corresponding to the spacing of said receptacles of said aforementioned conveying chains, said plates being held under compressive strain in the tension position to hold said workpieces, spring means connecting said plates to an index plate said index plate defining two running surfaces spaced from one another, a plate held under compressive strain against a roller, for the purpose of shifting said plates, said running surface which makes possible the axial shifting of said plates outwards, for the purpose of releasing said workpieces, lies over the entire thickness of the plate, and running surface which produces an axial shifting movement of said plates to seize said workpieces is provided on a partial region of said plate thickness, each said plate being movable with respect to a guide part in said bearing plate and the said roller being mounted by spring means on said guide part so as to be movable into the tension position, each said index plate being mounted freely-running on said guide shaft, a lever mechanism connected to said disc cam to effect movement of the said index plates about said guide shaft, against the chain movement, to move said roller from said running surface holding a plate in the waiting position, onto said running surface making possible the tension position, or from said running surface holding a plate in the tension position, onto said running surface producing the release position, and wherein said lever mechanism includes a cranked lever pivotable about a common axis, said lever having one arm guided in a curved track of said disc cam and the other arm flexibly connected to a link which in each case acts upon an index plate.

8. A transport device as recited in claim 7, in which said disc cam is synchronous in rotating movement with said bearing plates said chain wheels and said disc cam all said parts being connected to a common propulsion mechanism.

9. A transport device as recited in claim 6, wherein said delivery arrangement has a bearing plate equipped with rigid abutment surfaces and a bearing plate equipped with axially shiftable abutment surfaces.

10. Transport device as recited in claim 1, comprising four endlessly revolving conveying chains with receptacles arranged on them, for the two end regions of workpieces to be transported, two conveying chains arranged beside each other at a small spacing at each workpiece end region, said conveying chains arranged in pairs passing around a chain wheel and the chain wheels of said pairs of chains being adjustable and fixable in a rotation angle region in the longitudinal direction of the chains for the purpose of moving the chains to form different receptacles, and said chains of each pair of chains are variably spaced to one another, and both pairs of chains likewise being variably spaced to one another; each aforementioned receptacle which carries an end region of a workpiece is formed from two catches which are located on two adjacently running conveying chains and point towards each other, each catch defining surfaces which carry a workpiece arranged at least approximately on a vertical or inclined plane which runs in the longitudinal direction of said chains, the carrying surfaces of said catches running vertically or inclined in the direction of movement of the chains, to prismatic or rectangular receptacles, and a guide region of said chains wherein is located rotatable about their guide shaft, a delivery arrangement which delivers said workpieces from said conveying chain to a further transport arrangement, said delivery arrangement possessing two bearing plates having in each case several plates with slidable abutment surfaces which plates are arranged at an angular spacing which corresponds to the spacing of said receptacles, said plates are held, axially movable in said bearing plates and are connected by an index plate, actuated by a spring, to said running surfaces for the purpose of clamping and releasing said workpieces, said index plate is connected via a lever mechanism to a disc cam which, in dependence upon said conveying chain movement, produces a pivoting of the said index plate about said guide shaft against the chain movement, for the purpose of axially moving said plates.

11. A transport device wherein four conveyor chains moving in synchronism are provided, said chains being arranged in two pairs, each said pair being located in an end region of workpieces to be transported, said chains of each pair being adjacent to but spaced apart from one another,'each said chain of each said pair wheel, means being locatable in each said aperture such that each said chain wheel is adjustable relative to said other chain wheel mounted on said boss, and means locatable intermediate each said boss and one of said chain wheels mounted thereon whereby the axial spacing between each said pair of chain wheels mounted on said same boss is adjustable. 

1. A transport device, more especially for screen process machines, said device comprising parallel paired conveying chains, receptacles on said chains for the two end regions of workpieces to be transported, each said receptacle comprising two catches located on respective chains of each pair of conveying chains, each said pair of catches which form a receptacle being angled towards each other, a foot on each catch fastening it to one side of a respective chain, a lug on each catch pointed upwards and defining surfaces forming said receptacle, one of said surfaces on said catch forming an acute angle with said chains and the other one of said surfaces on said catch forming a right angle with said chains, whereby the surfaces of adjacent catches which stand at an acute angle to said chains form an angled receptacle and the surfaces of adjacent catches which stand at a right angle to said chains form a rectangular receptacle.
 2. A transport device as recited in claim 1 including means for relatively moving the chains which carry one end region of a workpiece to form differently dimensioned receptacles and chain wheels carrying said chains.
 3. A transport device as recited in claim 2, comprising a shaft, a boss on said shaft for a chain wheel, and means for effecting relative rotation between said boss and said wheel, and for then fastening said boss and wheel together.
 4. A transport device as recited in claim 3, comprising an adjustable distance piece between adjacent chain wheels.
 5. A transport device as recited in claim 1, wherein each link of said conveying chains is equipped in the region of their angular receptacles with an upward pointed lug as a support for a workpiece to be printed on two sides.
 6. A transport device, as recited in claim 1, comprising a delivery arrangement which is rotatable about a guide shaft to take over said workpieces from said conveying chains, rotate said workpieces through a certain turning range, and thereafter deliver them to a further transport arrangement provided with plates which are axially movable towards one another, to hold said workpieces clamped on oppositely situated sides, said plate having slidable abutment surfaces consisting of self-lubricating material.
 7. A transport device as recited in claim 6, wherein said delivery arrangement contains two oppositely situated bearing plates fastened to the said guide shaft plates, several axially movable plates spaced around said shaft at points corresponding to the spacing of said receptacles of said aforementioned conveying chains, said plates being held under compressive strain in the tension position to hold said workpieces, spring means connecting said plates to an index plate said index plate defining two running surfaces spaced from one another, a plate held under compressive strain against a roller, for the purpose of shifting said plateS, said running surface which makes possible the axial shifting of said plates outwards, for the purpose of releasing said workpieces, lies over the entire thickness of the plate, and running surface which produces an axial shifting movement of said plates to seize said workpieces is provided on a partial region of said plate thickness, each said plate being movable with respect to a guide part in said bearing plate and the said roller being mounted by spring means on said guide part so as to be movable into the tension position, each said index plate being mounted freely-running on said guide shaft, a lever mechanism connected to said disc cam to effect movement of the said index plates about said guide shaft, against the chain movement, to move said roller from said running surface holding a plate in the waiting position, onto said running surface making possible the tension position, or from said running surface holding a plate in the tension position, onto said running surface producing the release position, and wherein said lever mechanism includes a cranked lever pivotable about a common axis, said lever having one arm guided in a curved track of said disc cam and the other arm flexibly connected to a link which in each case acts upon an index plate.
 8. A transport device as recited in claim 7, in which said disc cam is synchronous in rotating movement with said bearing plates said chain wheels and said disc cam all said parts being connected to a common propulsion mechanism.
 9. A transport device as recited in claim 6, wherein said delivery arrangement has a bearing plate equipped with rigid abutment surfaces and a bearing plate equipped with axially shiftable abutment surfaces.
 10. Transport device as recited in claim 1, comprising four endlessly revolving conveying chains with receptacles arranged on them, for the two end regions of workpieces to be transported, two conveying chains arranged beside each other at a small spacing at each workpiece end region, said conveying chains arranged in pairs passing around a chain wheel and the chain wheels of said pairs of chains being adjustable and fixable in a rotation angle region in the longitudinal direction of the chains for the purpose of moving the chains to form different receptacles, and said chains of each pair of chains are variably spaced to one another, and both pairs of chains likewise being variably spaced to one another; each aforementioned receptacle which carries an end region of a workpiece is formed from two catches which are located on two adjacently running conveying chains and point towards each other, each catch defining surfaces which carry a workpiece arranged at least approximately on a vertical or inclined plane which runs in the longitudinal direction of said chains, the carrying surfaces of said catches running vertically or inclined in the direction of movement of the chains, to prismatic or rectangular receptacles, and a guide region of said chains wherein is located rotatable about their guide shaft, a delivery arrangement which delivers said workpieces from said conveying chain to a further transport arrangement, said delivery arrangement possessing two bearing plates having in each case several plates with slidable abutment surfaces which plates are arranged at an angular spacing which corresponds to the spacing of said receptacles, said plates are held, axially movable in said bearing plates and are connected by an index plate, actuated by a spring, to said running surfaces for the purpose of clamping and releasing said workpieces, said index plate is connected via a lever mechanism to a disc cam which, in dependence upon said conveying chain movement, produces a pivoting of the said index plate about said guide shaft against the chain movement, for the purpose of axially moving said plates.
 11. A transport device wherein four conveyor chains moving in synchronism are provided, said chains being arranged in two pairs, each said pair being located in an end region of workpieces to be tRansported, said chains of each pair being adjacent to but spaced apart from one another, each said chain of each said pair passing around a chain wheel, the pair of chain wheels for each said pair of chains being mounted on opposite sides of a boss, the bosses for said chain wheels being movably mounted on a common shaft in accordance with the length of workpieces to be transported, said chain wheels associated with each said boss having opposed lateral surfaces, said opposed lateral surfaces defining an aperture extending through each said chain wheel, means being locatable in each said aperture such that each said chain wheel is adjustable relative to said other chain wheel mounted on said boss, and means locatable intermediate each said boss and one of said chain wheels mounted thereon whereby the axial spacing between each said pair of chain wheels mounted on said same boss is adjustable. 